Merge pull request #29 from minamorl/patch-for-invalid-token-error

Handles cryptography.fernet.InvalidToken exception

aiohttp_session/cookie_storage.py

@@ -3,6 +3,7 @@
 import base64
 
 from cryptography import fernet
+from cryptography.fernet import InvalidToken
 
 from . import AbstractStorage, Session
 
@@ -30,10 +31,13 @@ def load_session(self, request):
         if cookie is None:
             return Session(None, data=None, new=True)
         else:
-            data = json.loads(
-                self._fernet.decrypt(cookie.encode('utf-8')).decode('utf-8')
-            )
-            return Session(None, data=data, new=False)
+            try:
+                data = json.loads(
+                    self._fernet.decrypt(
+                        cookie.encode('utf-8')).decode('utf-8'))
+                return Session(None, data=data, new=False)
+            except InvalidToken:
+                return Session(None, data=None, new=True)
 
     @asyncio.coroutine
     def save_session(self, request, response, session):

tests/test_encrypted_cookie_storage.py

@@ -78,7 +78,7 @@ def test_invalid_key(self):
         with self.assertRaises(ValueError):
             EncryptedCookieStorage(b'123')  # short key
 
-    def test_create_new_sesssion(self):
+    def test_create_new_sesssion_broken_by_fermat(self):
 
         @asyncio.coroutine
         def handler(request):
@@ -91,8 +91,15 @@ def handler(request):
 
         @asyncio.coroutine
         def go():
-            _, _, url = yield from self.create_server('GET', '/', handler)
-            resp = yield from request('GET', url, loop=self.loop)
+            key = fernet.Fernet.generate_key()
+            self.key = base64.urlsafe_b64decode(key)
+
+            _, _, url = yield from self.create_server(
+                'GET', '/', handler)
+            resp = yield from request(
+                'GET', url,
+                cookies=self.make_cookie({'a': 1, 'b': 12}),
+                loop=self.loop)
             self.assertEqual(200, resp.status)
 
         self.loop.run_until_complete(go())